1. Technical Field
The invention relates to the transport of cumbersome narrow oblong objects.
In particular, the invention relates to a transport aid for an A-frame type stepladder wherein the stepladder rolls upon a single wheel disposed adjacent one end, while being partially supported and propelled by a person holding a second end, with a narrow profile presented to facilitate passage through doors and around corners.
2. Prior Art
Narrow oblong objects, such as ladders, are often too heavy or cumbersome for convenient transport by clerks, warehouse personnel and home residents from one location in a store, warehouse, factory or residence to another without enlisting the assistance of a second person, especially when obstacles such as doors, corners and narrow passageways must be traversed.
Typical prior-art transport aids such as taught by Bjerkgard, U.S. Pat. No. 4,009,762 and by Brookes, et al., U.S. Pat. No. 4,049,283, dispose the narrow oblong object upon a plurality of wheels, with substantially horizontally disposed broad longitudinal surface presenting a relatively wide profile unsuitable for traversing doors, corners and narrow passageways. While the use of a plurality of wheels on a wide wheel-base resists tipping over during transport, such resistance is undesirable in many practical situations where tipping is necessary to traverse a combination of obstacles laterally displaced at various loci above the floor. The wheel means of prior art were cumbersome, either requiring detachment in order to place the narrow oblong object into use, or interfering substantially with said use.
The principle of the wheelbarrow is well known prior art, wherein a single wheel supports one end of the wheelbarrow, and handles with wide lateral displacement are provided at a second end for manual propulsion and to transmit manually applied torque to keep the wheelbarrow upright. The traditional wheelbarrow's horizontally separated propulsion handles necessarily produce obstacle interference problems similar to those described for the Bjerkgard and Brookes, et al. patents above. Further, the traditional wheelbarrow configuration has a relatively low center of gravity, wherein offset between the single wheel and a vertical plane of weight symmetry is less troublesome than when a narrow oblong object necessarily must be tipped so as to raise its center of gravity high above its lowest point in traversing obstacles. The wheelbarrow's horizontally separated handles distribute weight approximately equally between the user's hands, and application of simultaneous anti-tipping torque between those hands is relatively comfortable. Conversely, when a person attempts to propel one end of a narrow oblong object past an obstacle by grasping a lower edge with one hand, and an upper edge, separated by a substantial vertical distance from the lower edge, with the other hand, ability to exert anti-tipping torque between such handholds is reduced because the lower hand supports substantially all of the distributed weight. Any inherent imbalance tending to create a tipping moment in the hand-over-hand position is therefore undesirable.
Therefore, it is an object of the invention to provide a transport aid by which a person may propel a narrow oblong object traversing obstacles without the aid of another person.
Another object of the invention is to provide an aid for transport of a narrow oblong object wherein a narrow profile is presented to facilitate traversing obstacles.
A further object of the invention is to provide an aid for transport of a narrow oblong object wherein the need for the user to exert anti-tipping torque is minimized.
Still another object of the invention is to provide an aid for transport of a narrow oblong object capable of user-controlled angular disposition during transport to avoid combinations of obstacles at various loci above the floor.
A still further object of the invention is to provide an aid for transport of a narrow oblong object which does not substantially interfere with the utility of the object.
Another object of the invention is to specifically provide an aid for transporting a ladder by a person without the aid of another person.
Yet another object of the invention is to provide an aid for transport of a narrow oblong object easily attached and detached from the object, and transferable from one narrow oblong object to another.
A further object of the invention is to provide adjustable compensation for variations in a plane of weight symmetry of one transported object as compared to another transported object.